Known power shift transmissions use basic manual transmission architecture with a double clutch system as input. The drawback of such a system is that the system needs a relatively long axial installation space due to the double clutch system. The long axial installation space limits the number of gear ratios, especially in front wheel drive vehicles. Large number of gear ratios are desirable for good fuel economy. Further, known transmissions typically require a separate gear pair for each speed forward or backward speed ratio.
It is known to provide “gear multiplication” to a transmission by which the number of gears needed to provide a particular number of speed ratios is reduced. However, in order to implement the gear multiplication, “torque filling” is needed. Specifically, for shifts between certain speed ratios, for example from a third speed ratio to a fourth speed ratio, rather than switching between two separate lay shafts, the switch is made on the same lay shaft. Thus, to shift from the third speed ratio to the fourth speed ratio, the torque to the lay shaft must be interrupted. Without some intervention, a jolt or lurch occurs due to the torque interruption. To prevent the jolt or lurch, a speed ratio using a different lay clutch must be used during the torque interruption to provide torque to the transmission output. The need for torque filling increases cost and complexity of the transmission.